-LRB- CNN -RRB- -- `` Refugees are the most vulnerable people on Earth . They are fighting to survive . '' -- Angelina Jolie , United Nations High Commissioner for Refugees goodwill ambassador

Children play in floodwater at a Pakistan refugee camp after floods displaced residents in August 2008 .

The world 's population at the end of last year included 42 million displaced people , 80 percent of them in developing nations , according to a report this week by the Office of the United Nations High Commissioner for Refugees .

Many of these refugees are living in minimal standards for shelter and are exposed daily to the harshest elements of weather , the report says .

For example , in Pakistan , some 300,000 refugees are living outdoors , in tents or similar structures , said Michael Kocher , vice president of international programs for the International Rescue Committee .

That part of the world has been hit hard by extreme weather over the past couple of months . First , extreme heat plagued Pakistan , with temperatures in May and June soaring past 100 degrees Fahrenheit -LRB- 38 degrees Celsius -RRB- . The heat is escalating the discomfort for many .

`` People are living in cramped situations , often unsanitary situations , and it 's very hot , '' Kocher said . `` In many places , there is not enough clean water or adequate sanitation . Heat exacerbates that problem . ''

As World Refugee Day approaches -- it falls on Saturday this year -- the forecast calls for even more dramatic weather changes in the coming weeks . In Southeast Asia , long stretches of scorching temperatures are usually the prelude to the rainy , or monsoon , season . Watch Angelina Jolie talk to CNN 's Anderson Cooper about the world 's refugee problem ''

The term `` monsoon '' refers to a seasonal reversal of wind that typically occurs in late June or early July . For countries like Pakistan and India , this change brings daily , nonstop downpours .

The change in the weather is essential for local crops , according to John Fasullo , project scientist with the National Center for Atmospheric Research .

`` The Southeast Asian monsoon is the key source for regional agriculture , '' he told CNN . `` It provides the majority of the moisture to support food needs for one-half the world 's population . ... It also brings a beneficial cooling of the temperatures . ''

The problem is , monsoon rains can also cause devastating floods . Fasullo says the threat for flooding can be `` continual from late June through early September . ''

In Pakistan , for example , where agencies have witnessed a large increase in displaced people over the past year , the monsoon of 2008 was particularly intense .

If 2009 brings similar floods to the country , there will be a new threat for refugees exposed to the storms : mud . Watch how the monsoon is affecting refugees ''

`` The camps are quite threadbare , '' Kocher said . `` Tents are held to the ground by rope . It 's hard to keep people dry . The ground gets muddy , which can lead to dirty water and bad sanitation facilities . ''

Vulnerability to nature 's dangerous elements is not only a concern for people displaced in Pakistan . Refugees in Afghanistan are subject to brutal winters , while in Iraq , scorching heat and sandstorms are common challenges for those without sufficient shelter .

Of World Refugee Day , actress and humanitarian Angelina Jolie says , `` Please do not forget them , and remember them on this day . ''

Here are answers to some commonly asked questions :

• How can I help world refugees that are exposed to the monsoon season and other weather dangers ?

Go to CNN.com / ImpactYour World . There , you will find links to charities that help refugees and others in need .

• Does the monsoon season affect the weather in the United States ?

Southern Arizona and parts of New Mexico see heavy rain during the North American monsoon season , which runs from June 15 through September 30 . This time of year , the wind shifts , tapping into moisture from the Gulf of California and the Gulf of Mexico , and producing strong thunderstorms that bring the majority of the region 's annual rainfall .

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As World Refugee Day approaches , monsoons could compound refugees ' troubles

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World contains 42 million displaced people -- 80 percent in developing nations

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In Pakistan , the 2008 monsoon season brought rains that flooded refugee camps

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UN Goodwill Ambassador Angelina Jolie : `` Please do not forget them ''